Stadjer

What I mean with swarm behaviour is the order in the chaos, like in big flocks of birds or swarms of insects no one leads, no one follows, no one has oversight over the whole process but if every individual is considerate to the ones directly besides and in front it functions without collisions.

I'll try to reconstruct the unwritten rules here, because they are unspoken too and it's more something that happens automatically through experience from a young age. A written rule is for example that you stick out your hand before making a turn, but a lot of people don't do that because they're on the phone, carrying a painting or breat feeding or just don't care. But they will stop pedalling and 'prepare' for the turn, that's what others will pick up automatically. If you do stick out your hand but keep on biking like you're going straight you probalby have a bigger chance of surprising others. Also if people want to cross a zebra, if you stop pedalling for a second they (not tourists) will know you have seen them, start crossing and you can bike through behind their back without losing momentum. There's a lot more body language, you can also see in the video I linked that some are assertive, and some ride defensive, but the assertive ones show they are about to claim space or priority by attitude and often more forward positioning, so if they make a move to use a tiny gap it surprises no one. If you take a defensive attitude and suddenly change your mind a make an assertive move that will surprise the others. I Surprise is what causes collisions. If body language is not clear about the intentions or people will make eye contact and negotiate. Usually the front wheel points in the direction people want to go so it signals whether you try to go in front or around the rear, if you want to make a left turn at a crossing and are pointing towards an oncoming cyclist and you 'open' your wheel first it shows you'll go around the rear and the other will not take evasive action towards you. Use your ears, it will give an impression of what comes from behind, the bell gives a lot of information about the distance, speed and angle, and an urgent warning usually sounds different than a cyclist that just wants you to know he's there. Don't turn your head and leave the straight line, it usually means 'don't move' other than forward. So I think the main unwritten rules are: Be predictable, predict and prepare to improvise in a predictable way.

It's really notthing special, just human behaviour. It's simular to why people in airports or other big crowds don't bump into eachother much. It's just on bikes so it happens a bit faster.